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Aberdeen Royal Hospitals
University of Aberdeen
Department of Bio-Medical Physics & Bio-Engineering
Foresterhill Aberdeen AB25 2ZD
The Honorable Charles S. Jeffress
Assistant Secretary of Labor
for Occupational Safety and Health
OSHA Docket Office
Docket No. S-777
U.S. Department of Labor
Room N-2625
200 Constitution Avenue, NW
Washington, DC 20210
June 23, 2000
Dear Mr. Jeffress:
Thank you for the opportunity to submit post-hearing comments
on OSHA's proposed standard on occupational exposure to ergonomic
hazards. As in my earlier comments to the record, I remain supportive
of OSHA's effort to regulate ergonomic hazards. I must reiterate
the following concerns, however, and I will expand on some of
them below:
- The standard should include injuries caused by slips, trips
and falls in the definition of MSDs.
- The standard should recognize sudden, unexpected loading
as an ergonomic risk factor.
- The standard should accept elastic back supports as ergonomic
PPE.
- The standard should acknowledge the large body of scientific
data demonstrating the effectiveness of elastic back supports
as PPE.
- The standard should reference the positive results of the
recent NIOSH laboratory study on back support efficacy; this
study has been peer reviewed.
- NIOSH's unpublished epidemiological study on the use of back
supports at Wal-Mart should not be referenced in the proposed
rule until the peer review process is completed.
- The proposed standard should apply to agriculture, construction
and maritime operations.
For the most part, my concerns are linked to my research and
that of several of my peers. This research has found that sudden,
unexpected loading of the spine often is the contributing "first
event" in those back injuries that result in lost time from
work. This research has found that the operative mechanism during
such events is the overreaction of the back muscles in response
to sudden loading. In other words, the "hazard" in
these events is internal. It comes from the worker's own body.
Elastic back supports have been clinically proven effective
in significantly reducing this uncontrolled over-contraction
of the back muscles. These products have been shown to reduce
the back muscles' overreaction to sudden, unexpected loading
by a factor of one third. The back support acts as a "barrier"
against potential self-injury resulting from the body's autonomic
processes during accidents.
In addition, elastic back supports have been shown to reduce
pressure on a target tissue (the disc) by:
- Increasing intra-abdominal pressure.
- Decreasing EMG (muscle force).
- Decreasing EMG fatigue (muscle force).
- Decreasing motion-decreases antagonistic muscle activity.
- Bypassing lumbar spine to ribs.
Because they are proven effective at reducing back injuries
through a number of mechanisms, back supports should be recognized
as effective personal protective equipment in the proposed standard.
In the past, OSHA has asserted that elastic back supports
are not PPE. They reason that these products do not protect against
external hazards by forming a physical barrier as do accepted
types of PPE. The same limitation-the absence of a physical barrier
that prevents or minimizes contact with a solid external hazard-is
true, however, for the several other types of PPE that OSHA has
long accepted.
Hearing protection, for instance, does not prevent contact
with the body by a physical object, but rather it prevents the
impact of an outside force (noise) on the body. Similarly, back
supports prevent external forces such as sudden loading from
impacting the spine and supporting back musculature. Hard hats
do not just minimize contact by external hazards, they also redistribute
external forces to limit damage to the body. Knee pads, a form
of ergonomic PPE called out in the proposed rule, also redistribute
external force. Back supports function the same way, redistributing
external forces so as to reduce their impact on the body. Clearly,
the same logic by which OSHA recognizes these other forms of
PPE should enable the agency to recognize the role of back supports
as well.
Failing to acknowledge the scientifically proven benefits
of elastic back supports and their role as PPE is a serious departure
from the accepted hierarchy of controls, and I encourage OSHA
to correct this oversight in the future.
As for OSHA's decision to exclude the agriculture, construction
and maritime industries from coverage, I believe this is a serious
error. Not only is OSHA's discretion to promulgate a standard
piecemeal limited by the U.S. courts, it seems to me that the
decision to only include general industry in the standard is
based on inadequate knowledge of MSD causes in the excluded industries
and an inability to offer a remedy. A better understanding of
the impact of unexpected spinal loading and the positive intervention
of using elastic back supports should make it clear to OSHA that
solutions do exist for the excluded industries.
Accidents caused by unexpected loading of the spine are a
significant contributor to MSD injuries in the agriculture, construction
and maritime industries. The availability of a proven means of
reducing exposure to this hazard justifies extension of the standard,
and the high percentage of these types of injuries that occur
in these industries makes it imperative. The fact that this intervention
is simple and cost effective is further justification, and it
overcomes the argument that expansion of the standard to these
industries would seriously impede the rulemaking process. Awareness
of this recently identified cause and remedy make it incumbent
on OSHA to include agriculture construction and maritime operations
in the initial phase of the proposed rule.
I strongly recommend that OSHA adopt these recommended changes
in the final rule so as to better accomplish its mission of protecting
the health of American workers.
Respectfully,
Malcolm H. Pope, Dr. Med. Sc., Ph.D.
Liberty Safe Work Professor
Liberty Safe Centre
University of Aberdeen, Scotland
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